Hydrianum | |
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Hydrianum ovale | |
Scientific classification | |
Clade: | Viridiplantae |
Division: | Chlorophyta |
Class: | Chlorophyceae |
Order: | Chlamydomonadales |
Family: | incertae sedis |
Genus: | Hydrianum Rabenhorst, 1868 |
Type species | |
Hydrianum ovale Rabenhorst [1] | |
Species [1] | |
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Synonyms | |
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Hydrianum is a genus of green algae, in the order Chlamydomonadales. It is found in freshwater habitats such as marshes and bogs, as an epiphyte on plants or other algae. [1] It is common, but most likely overlooked due to its similarity with similar genera such as Characium . [3]
Hydrianum consists of solitary or clustered cells attached to a substrate, via a mucilaginous pad or a stipe. Cells are cylindrical, oval, or spindle-shaped; in some species they are distinctly curved. Cells are uninucleate (with a single nucleus), they contain a single parietal chloroplast (or multiple when older). Pyrenoids are generally absent but may be present in a few species. [1]
Asexual reproduction occurs via the formation of zoospores; the zoospores are released through a rupture near the apex of the cell wall, while one zoospore stays behind and develops into a new vegetative cell. Zoospores have two flagella and a single chloroplast. After swimming, the zoospores settle and develop into a new cell. Sexual reproduction has not been observed in this genus. [1]
Members of Hydrianum with a pyrenoid can be confused with Characium, but in Hydrianum the zoospores exit subapically or apically, while in Characium the zoospores exit through a lateral opening. Additionally, in Hydrianum a zoospore may remain in the sporangium and develop into a new cell. The genus is also similar to Characiopsis , which generally lacks pyrenoids, but is unrelated. [3]
The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. They are usually green due to the dominance of pigments chlorophyll a and chlorophyll b. The chloroplast may be discoid, plate-like, reticulate, cup-shaped, spiral- or ribbon-shaped in different species. Most of the members have one or more storage bodies called pyrenoids located in the chloroplast. Pyrenoids contain protein besides starch. Some green algae may store food in the form of oil droplets. They usually have a cell wall made up of an inner layer of cellulose and outer layer of pectose.
Chlorococcaceae is a family of green algae, in the order Chlamydomonadales. They are mostly soil-dwelling algae. Many members of this group produce lipids and secondary carotenoids.
Carteria is a genus of green algae in the family Chlamydomonadaceae. Carteria are similar in morphology to the common genus Chlamydomonas and differ by having four, rather than two, flagella at the vegetative stage.
Characiochloris is a genus of green algae in the family Characiochloridaceae. Characiochloris is epiphytic on freshwater algae, or found in soil.
Characiopodium is a genus of green algae in the family Sphaeropleaceae. It occurs in soils.
Characiosiphon is a genus of green algae in the family Characiosiphonaceae. It contains a single species, Characiosiphon rivularis.
Characium is a genus of green algae in the family Characiaceae. It is very commonly found in freshwater habitats, where it is attached to phytoplankton or zooplankton.
Lobocharacium is a genus of green algae in the family Characiosiphonaceae. It contains the single species Lobocharacium coloradoense. It has been isolated from a pond in Colorado, United States.
Palmellopsis is a genus of green algae, specifically of the Palmellopsidaceae. They are either planktonic or attached to substrates in fresh water, or in aeroterrestrial habitats.
Planktosphaeria is a genus of Chlorophyceae of the green algae. It was first described by the phycologist Gilbert Morgan Smith in 1918, with Planktosphaeria gelatinosa as its type species. Species of Planktosphaeria are commonly found in freshwater plankton around the world.
Vitreochlamys is a genus of green algae in the family Chlamydomonadaceae. It is sometimes known by the name Sphaerellopsis, published by Aleksandr Arkadievich Korshikov. However, that name is an illegitimate later homonym, preceded by SphaerellopsisM.C.Cooke. It is commonly found in freshwater habitats.
Characiellopsis is a genus of green algae in the family Characiaceae. Two species are known: Characiellopsis anophelesii and Characiellopsis skujae.
Deuterocharacium is a genus of green algae in the family Characiaceae. It is found in freshwater habitats, attached to algae or detritus. It is rare and has only been recorded from Europe.
Desmatractum is a genus of green algae, in the order Chlamydomonadales. It is found in freshwater habitats such as ponds, ditches, and bogs as plankton or metaphyton. The genus is cosmopolitan, but some species are very rare.
Follicularia is a genus of green algae, in the family Schizochlamydaceae. It is found in terrestrial habitats, mainly soil.
Korshikoviella is a genus of green algae in the family Characiaceae.
Chlorokybus is a multicellular (sarcinoid) genus of basal green algae or charophyte. It has been classified as the sole member of the family Chlorokybaceae, which is the sole member of the order Chlorokybales, in turn the sole member of the class Chlorokybophyceae. It grows on soil and rock surfaces, and is rare.
Cecidochloris is a green algae genus in the family Chlorangiellaceae. It occurs in freshwater. However, it has only been reported so far from Europe, with an additional species from India that is incompletely described.
Bracteamorpha is a genus of green algae in the order Sphaeropleales, and is the only genus in the family Bracteamorphaceae. It contains a single species, Bracteamorpha trainorii.
Apiocystis is a genus of algae belonging to the family Tetrasporaceae. It is found attached to freshwater aquatic algae or plants. The species of this genus are found in Europe and Northern America, and are widespread but generally uncommon.